French researchers have discovered how tattoo ink is transmitted from dying cells to living ones, paving the way for better erasure techniques.
The human skin is constantly renewed, yet it has this amazing ability to keep the drawings on its surface for decades.
The French capital Paris is hosting from Friday to Sunday the largest convention in the world of tattoo artists. In the meantime, scientists gathered at the Immunology Center of Marseille-Luminy think they understood how tattoos manage to last for so long despite the constant shedding of skin, refusing the belief that “the cell carrying the pigments lived forever”.
“This hypothesis is questioned,” said in a statement the National Institute of Health and Medical Research.
The essential question id: in what type of cell is the ink housed? It was long believed tattoo inks settle in the fibroblasts, the cells of the dermis, which among others allow healing.
However, it has been discovered that they are actually located in the macrophages, specialized immune cells that defend the body against infectious agents by ingesting them.
These macrophages, it seems, do the same thing with ink. And they pass it generation after generation.
“This cycle of capture, release and recapture of the pigment occurs continuously in tattooed skin,” according to the French researchers.
The phenomenon was observed on the tail of a mouse tattooed in the laboratory. Not just any mouse, a “genetically modified one that can kill macrophages in the dermis” to speed up the process.
“The appearance of the tattoo did not change” because “dead macrophages released the pigment in the surrounding area where, in the following weeks, this pigment was reabsorbed by new macrophages,” say the scientists.
This discovery should find its application in the complicated operation of removing tattoo ink, to erase a tattoo.
The promising technique consists of “laser pulses that cause the death of skin cells and the release and fragmentation of their pigments”, namely “the temporary elimination of macrophages present in the tattoo area”. All that remains is to remove the ink by “the lymphatic vessels that drain the skin”.